Hard disk drives are common information storage devices. FIG. 1A provides an illustration of a typical disk drive unit 100 essentially consisting of a series of rotatable disks 101 mounted on a spindle motor 102, and a Head Stack Assembly (HSA) 130 which is rotatable about an actuator arm axis 105 for accessing data tracks on disks during seeking. The HSA 130 includes at least one drive arm 104 and HGA 150. Typically, a spindling voice-coil motor (VCM) is provided for controlling the motion of the drive arm 104.
Referring to FIG. 1B, the HGA 150 includes a slider 103 having a reading/writing transducer (not shown) imbedded therein, a HGA suspension 190 to load or suspend the slider 103 thereon. When the disk drive is on, a spindle motor 102 will rotate the disk 101 at a high speed, and the slider 103 will fly above the disk 101 due to the air pressure drawn by the rotated disk 101. The slider 103 moves across the surface of the disk 101 in the radius direction under the control of the VCM. With a different track, the slider 103 can read data from or write data to the disk 101.
FIG. 1C shows a conventional HGA suspension, the HGA suspension 190 includes a load beam 106, a base plate 108, a hinge 107 and a flexure 105, all of which are assembled together.
The load beam 106 is connected to the base plate 108 by the hinge 107. The base plate 108 is used to enhance structure stiffness of the whole HGA 150. The flexure 105 runs from the hinge 107 to the load beam 106. The flexure 105 has a distal end 119 adjacent the hinge 107 and a proximal end 118 adjacent the load beam 106. A suspension tongue 116 is provided at the distal end of the flexure 105 to carry the slider 103 thereon.
Conventionally, a plurality of electrical traces (not shown) is formed on the flexure 105 along length direction thereof. More specifically, the electrical traces begin with the proximal end 118 and terminate at the distal end 119. The HGA suspension tongue 116 has a plurality of probes (not shown) formed thereon for coupling the slider 103.
Conventionally, sliders are fixedly mechanically mounted to the HGA suspension by adhesive and electrically connected to the probes on the HGA suspension tongue by solder balls. Testing such as dynamic performance testing is typically performed on the suspension before the HGA including the slider and the HGA suspension incorporated into a disk drive. Those sliders in the HGA which are concluded to be non-defective as a result of the testing are incorporated into HSA into an actual disk drive. Those sliders in the HGA which are judged to be defective are rejected with the HGA suspension. If a slider is rejected as defective, therefore, its HGA suspension will be rejected, resulting in an increase in cost. Possibly, defective slider may be removed from their HGA suspensions so that the HGA suspension can be reused. However, this operation is troublesome and may damage the HGA suspensions, as the slider is connected with the HGA suspension by glue and solder ball.
To solve these issues, a slider supporting apparatus for testing sliders has been developed. The slider supporting apparatus has a load beam, flexure, etc., constructed in the same manner as those of HGA suspension and can be movably fitted with a slider, so that the slider can be tested on the apparatus. After that, a good slider will be mounted on an HGA suspension without testing.
As shown in FIG. 2, a conventional slider supporting apparatus 200 includes a tongue 201, a pair of bellows portion 203 as springs, a first support portion 204, a second portion 205, etc., which constitute a part of a flexure 20. Each bellows portion 203 has a top and bottom that are formed by plastic deformation. This formation may be achieved by corrugating a part of the flexure 20 in its thickness direction like waves. The slider 290 is placed on the tongue 201 with the bellows portions 203 stretched in the direction of arrow T by means of a jig not shown. Thereafter, the bellows portions 203 are released from the applied tension, whereupon the slider 290 is clamped between the support portions 204 and 205. When the disk in the slider tester is rotated at high speed with respect to the slider 290, the slider 290 flies above the disk. Various checks are performed in this state. After the checks are finished, the slider 290 is removed from between the support portions 204 and 205 by stretching the bellows portions 203 with the jig. The sliders which are judged to be unacceptable by the checks are abandoned.
To increase the stroke of the bellows structure, the number of bellows may be increased. However, the length of the spring structure cannot be increased and is limited by the size of the slider structure. Thus, the stroke for extension and contraction is short. Moreover, the bellows portions 203 apply an undesirable out of plane moment tending to pop the slider 290 out of the tongue due to manufacturing tolerances during the plastic forming of the bellows. The moment can also contribute to generating pitch and roll static torque R, contributing to load and unload magnetic media damage and slider media contact during the slider testing.
Accordingly, an improved slider supporting apparatus has been developed. As shown in FIG. 3, the slider supporting apparatus 300 includes a flexure 30 formed of a metal plate having spring characteristics. The flexure 30 has a tongue 301 to be mounted with the slider 390, a pair of outrigger portion 302, first support portions 303, a second support portion 304, and a spring portion formed of a pair of flat springs 305, left and right, etc. Each flat spring 305 has a plurality of U-shaped convexes and inverted U-shaped concaves. The convexes and the concaves are alternately formed in the front-back direction of the flexure 30 along the surface direction of the flexure 30 as a zigzag shape. Although the zigzag design could reduce pitch and roll static torque, the alternating concaves and convexes provide a low out of plane stiffness and a large exposed real estate area susceptible to windage excitation during the loading onto a rotating magnetic medium during slider testing. Windage excitations cause out of plane vibration imparted to the slider 390 during write read operation leading to off track motions. Thus the number of zigzags is needed to reduce to reduce the windage excitation, which in turns limits the spring stroke of the flat springs 305, however.
Thus, there is a need for an improved slider supporting apparatus that can provide a larger stroke with long lifetime, meanwhile avoid pitch and roll static torque to prevent the slider popping out.